Modular edge form system for cast in place suspended concrete slabs

ABSTRACT

A modular edge form system for cast in place suspended concrete slabs, comprising wood or metal edge forms that close gaps between joists when a row of joists is above vertical supporting structures. The edge forms may depend on joists directly, or by means of wood edge form support structures; the joists in turn depend on joist hangers. Areas in front of the butt ends of joists are covered by means comprising the use of notch cover plates and/or bendable notch cover rectangles. The edge form system contains and supports cast-in-place horizontal concrete structures when they are poured and while they cure.

I claim the benefit of the filing date of provisional application61/206,697 filed on Feb. 3, 2009.

BACKGROUND OF THE INVENTION

Cast In Place suspended concrete slabs often have a haunch where theslab intersects vertical support structures, such as beams, girders, orwalls. Formwork for constructing slabs often comprises a series ofparallel joists that support top plywood sheathing. The joists aretypically supported directly by the vertical support structures. Joistsupport means comprise re-useable adjustable hangers, and one-time usehangers or saddles, having elements that become permanently embedded inthe structure. Because the top plywood sheathing is above the horizontalsurfaces of vertical support structures, there is an edge gap from eachjoist to one or both adjacent joists. Edge forms are used to close thisedge gap. One simple means often used by contractors is to nail or screwvertical plywood sections, or 1× lumber (such as 1×4's, 1×6's) to thebottom edge of the top plywood sheathing. This technique haslimitations: the top plywood sheathing can deflect between the joists,and for higher haunches there is no means for supporting the bottomagainst the beam or girder.

Closing the edge gap should be seen as the minimum requirement of anedge form or edge form system. A more optimal modular edge formingsystem of the present invention comprises these structural and designelements: means for use with adjustable and reusable hangers suspendedon a top surface of a vertical support structure; means for closing theedge gap for a range of haunch heights from zero to eight inches, ormore; deflection support for the edges of top plywood sheathing; meansfor bracing an edge form against a vertical support structure to preventor minimize leaking of concrete; means for forming suspended concreteslabs with curved perimeters; cooperative modular elements that can becombined in one or multiple way(s), as needed for a particularapplication; design and/or structural integration with other modularsystems for forming suspended slabs; minimal or no use of nails and/orscrews, resulting in faster and easier assembly and tear down, and norusted nails remaining on the site for years.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises means for closing edge gaps between rowsof joists used for concrete formwork, when the joists are abovevertically supporting structures.

In a first embodiment, metal edge forms, having front faces, a topflange which depends on the ends of joists, one or more bottomreinforcing flange sections, and optionally a bottom flange reinforcingfold, and notches and/or side half-notches, sized with respect to theouter width of joist hangers, are held against the edge of a verticallysupporting structure by sized notch cover plates having faces that arewider than the metal edge form notches and/or adjoining half-notches,and having tongues that are inserted between the butt end of a joist andthe inner central wall of its supporting joist hanger. A wedge shim maybe inserted behind the notch cover plate, to effect a tight fit of thejoist within a pair of joist hangers. The joist hanger depends on thevertically supporting structure. The metal edge form flanges and joistsare covered with dimensioned top sheathing, such that the edge of thesheathing is aligned with the front face of the metal edge forms.Surfaces of the supporting vertical structures, the metal edge forms,the notch cover plates, and the top sheathing contain and supportcast-in-place horizontal concrete structures, typically including rebarand/or other structural elements, when they are poured, and while theycure.

In a second embodiment, wood edge forms, having front faces and uppersupport structures on each side, depend upon top wood edge form supportstructures, having wood edge form upper support housings on each sidewhich engage with and support the wood edge form upper supportstructures, and having a top plate which depends on a joist. The joistsin turn are supported by joist hangers; the joist hangers in turn dependon a vertical support structure. Embodiments of the top wood edge formsupport structures comprise a variant having gaps between a front facecentral tongue and outer front surfaces, allowing the central tongue tobe inserted within a joist hanger when low haunches are required, and avariant with a continuous front face, used when the haunch height ishigh enough for the entire side face to be above the top of the joisthanger. When needed, at each joist butt end, sized notch cover plateshaving a central lower tongue may be inserted between the butt end of ajoist and the inner central wall of its supporting joist hanger,supported from behind by the joist, and comprising faces that are sizedto the outer width of the joist hangers, and recessed outer flangessized to hold the wood edge forms against the edge of the verticallysupporting structure. The two top wood edge form support structureembodiments can also be modified by adding angled support side platesthat are perpendicular to the edge of the vertical support structure, toprovide additional support in holding the wood edge forms against theedge of the vertically supporting structure. A wedge shim may beinserted behind the notch cover plate, to effect a tight fit of thejoist within a pair of joist hangers. Additional bendable notch coverrectangles, or in some cases duct tape, may be used to close gaps. Thewood edge forms and joists are covered with dimensioned top sheathing,such that the edge of the sheathing is aligned with the front face ofthe wood edge forms. Surfaces of the supporting vertical structures, thewood edge forms, the top wood edge form support structures, the notchcover plates, additional bendable notch cover rectangles, duct tape, andthe top sheathing contain and support cast-in-place horizontal concretestructures, typically including rebar and/or other structural elements,when they are poured, and while they cure.

Wedge shims used to effect a tight fit of a joist supported within andbetween a pair of joist hangers may further comprise symmetricalhorizontal slits and slit depth alignment lines, dimensioned to allowupper portions of the shim to be snapped off if necessary.

It will be understood that embodiments of joist hangers of the presentinvention may be adjustable. It will be further understood that whileembodiments of the present invention presented are rendered with respectto vertical edge gaps, the present invention can, with suitablemodifications, also be practiced for edge gaps that are set at an angleto the vertical plane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a joist hanger of the present invention,having a vertical hanger support structure, and depending on a verticalsupport structure.

FIG. 2 is a perspective view of a metal edge form of the presentinvention, with additional isometric perspectives.

FIG. 3 is an exploded and perspective view of notch cover plates of thepresent invention, together with shim, joist, and joist hanger elements,with additional isometric perspectives.

FIG. 4 is a perspective view of wood edge form elements of the presentinvention, with additional isometric perspectives.

FIG. 5 is a perspective view of top wood edge form support elements andwood edge form elements of the present invention, with additionalisometric perspectives.

FIG. 6 is a perspective view of top wood edge form support elements andwood edge form elements of the present invention, with additionalisometric perspectives.

FIG. 6A is a perspective view of top wood edge form support elements andwood edge form elements of the present invention, with additionalisometric perspectives.

FIG. 6B is a perspective view of top wood edge form support elements andwood edge form elements of the present invention.

FIG. 7 is an exploded and perspective view of notch cover plates of thepresent invention, together with shim, joist, and joist hanger elements,with additional isometric perspectives.

FIG. 8A is an exploded view of metal edge form, notch cover plates,shim, joist, and joist hanger elements, of the present invention,situated with respect to a vertical support structure edge line.

FIG. 8B is a partially exploded and partially assembled view of metaledge form, notch cover plate, shim, joist, and joist hanger elements, ofthe present invention, situated with respect to a vertical supportstructure edge line.

FIG. 8C is an assembled view of notch cover plate, shim, joist, andjoist hanger elements, of the present invention, situated with respectto a vertical support structure edge line, and prior to finalpositioning of a metal edge form element.

FIG. 8D is a fully assembled view of metal edge form, notch cover plate,shim, joist, and joist hanger elements, of the present invention,surmounted by top plywood sheathing, and situated with respect to avertical support structure edge line.

FIG. 9A is a partially exploded and partially assembled view of woodedge form, notch cover plate, shim, joist, joist hanger, and notch coverrectangle elements, of the present invention, situated with respect to avertical support structure edge line.

FIG. 9B is an assembled view of notch cover plate, shim, joist, joisthanger, and top plywood sheathing elements, of the present invention,situated with respect to a vertical support structure edge line, priorto final positioning of notch cover rectangle elements.

FIG. 9C is an assembled view of notch cover plate, shim, joist, joisthanger, notch cover rectangle, and top plywood sheathing elements, ofthe present invention, situated with respect to a vertical supportstructure edge line.

FIG. 9D is an assembled view of a low haunch configuration of shim,joist, joist hanger, and top plywood sheathing elements, of the presentinvention, situated with respect to a vertical support structure edgeline, and prior to final position of a notch cover rectangle elementwith tongue.

FIG. 10 is a perspective view of a wedge shim of the present inventionhaving symmetrical horizontal slits and slit depth alignment lines.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a modular haunch forming system for formingcast in place suspended concrete slabs. Elements comprising the systemwill first be presented and illustrated individually, followed byexplanations and illustrations of the elements in use, individually, incombination with other elements, and in combination with other modularsystems for forming suspended slabs. It should be noted that whiledimensions will be indicated for certain embodiments based on U.S.construction industry standards, the present invention can be practicedwith embodiments having other dimensions.

FIG. 1 illustrates an embodiment of one modular element of the presentinvention, comprising an adjustable and reusable joist hanger, 101,supported vertically by a top lip, 102, depending on top surface of avertical support structure, 151. The embodiment of the vertical supportstructure of FIG. 1 is a steel I-beam, 152, having a horizontal topflange, 153, and a recessed inner web, 154. A vertical hanger supportstructure, 104, in this embodiment a section of 2×4 lumber, is attachedto central face, 103, of the joist hanger, 101. The vertical hangersupport structure, 104, provides vertical support for the joist hanger,101. Some vertical support structures, such as walls or preformedconcrete girders, have a vertical side of sufficient length such that avertical hanger support structure, 104, is not required. The joisthanger, 101, supports a joist, 130, resting on a top plate within thehanger body (not shown). The height of the joist, 130, can be adjustedby means of the screw part, 120.

FIG. 2 illustrates an embodiment of a metal edge form, 201, of thepresent invention, comprising a front face, 202, a central hanger notch,203, a right hanger half notch, 204, a left hanger half notch, 205, acentral upper notch cover, 206, a right upper half notch cover, 207, aleft upper half notch cover, 208, a top flange, 209, a top flangecentral nailing hole, 210, bottom reinforcing flange sections, 211, andbottom flange reinforcing folds, 212.

FIG. 3 illustrates three embodiments of sized notch cover plates of thepresent invention, for use with the metal edge form, an embodiment ofwhich is shown in FIG. 2. Referring to FIG. 3, all three notch coverplate embodiments comprise a central metal edge form notch cover bottomtongue, 254. The metal edge form 2″ notch cover plate, 251, comprises ametal edge form 2″ notch cover upper plate, 256, that is 4″ wide and 2″high. The metal edge form 4″ notch cover plate, 252, comprises a metaledge form 4″ notch cover upper plate, 257, that is 4″ wide and 4″ high.The metal edge form 6″ notch cover plate, 253, comprises a metal edgeform 6″ notch cover upper plate, 258, that is 4″ wide and 6″ high.

The assembly of the sized notch cover plates is similar for the threeembodiments, 251, 252, and 253, illustrated in FIG. 3. Referring to thetop left exploded view, the bottom edge of the metal edge form notchcover shim, 255, is aligned with the bottom edge of the upper plate,256, and is between the upper plate, 256, and the notch cover bottomtongue, 254. The upper edge of the notch cover bottom tongue is alignedwith the upper edge of the notch cover shim, 255. Both the notch coverbottom tongue, 254, and the notch cover shim, 255, are centered withrespect to the center point of the bottom edge of the upper plate, 256.The three elements can be spot welded at the center. For additionalreinforcing, the notch cover shim, 255, can also be spot welded on eachside to the upper plate, 256. All elements comprising the sized notchcover plates for the metal edge forms can be made of mild steel.Embodiments of the sized notch cover plates may have upper plates in asized range of heights.

The thickness of the upper plates, 256, 257, and 258, must be such as toprovide sufficient stiffness when the notch cover plates support themetal edge forms from behind against the weight and impact of pouredconcrete. The thickness and dimensions of the notch cover bottom tongue,254, must be both thick enough to securely anchor the notch coverplates, 251, 252, and 253, between the inside of the joist hanger body,105, of an adjustable and reusable joist hanger, 101, and the butt endof a joist, 130, and must be thin enough to ensure they can be insertedeven when joists, 130, are already snug against the inside of the hangerbody, 105. The thickness and dimensions of the notch cover shim, 255,must be such as to provide sufficient added stiffness to the bottom ofthe of upper plates, 256, 257, and 258, when the notch cover plates,251, 252, and 253, support metal edge forms from behind against theweight and impact of poured concrete, and to provide space for an uppersection, 172, of a wedge shim, 171, that may optionally be placedbetween the notch cover plates, 251, 252, and 253, and the butt end of ajoist, 130, such that an upper section, 172, of a wedge shim, 171, thatmay be above the top edge of the bottom tongue, 254 will not engage withthe back of the upper plates, 256, 257, and 258, pushing the notch coverplate away from the butt end of a joist, 130.

FIG. 4 illustrates three embodiments of rectangular wood edge forms ofthe present invention. Embodiments of wood edge forms can be made ofthree quarter inch thick plywood, or 1× lumber, (examples: 1×4, 1×8). Afirst embodiment, 301, comprises a sized rectangular section of threequarter inch plywood, having a front face, 304, four sides perpendicularto the front face, 304, two vertical support top slits, 305, and twoupper support structures, 307. Multiple embodiments of the upper supportstructure, 307, are illustrated in FIG. 4. The vertical support topslits, 305, are approximately 1.5 inches deep. The first embodiment ofthe upper support structure, 308, further comprise a side edge that isperpendicular to both the front face, 304, and the upper side, 306, andis planar with the vertical sides. The second embodiment of the uppersupport structure, 309, further comprises an upper support structureangled side, 311, rendered such that the wider bottom side, 314, of thesecond upper support structure, 309, is recessed from the perpendicularside, 315, no more than half the depth of the vertical support top slit,305, when this slit depth is measured from the perpendicular side, 315.The third embodiment of the upper support structure, 310, furthercomprises a right rear beveled side, 312, having an angle ofapproximately 20 degrees to 30 degrees, and running the length of theright perpendicular side, 316, and a right upper support structure frontchamfer, 313, with a depth of approximately one quarter inch, andrunning no more than half the depth of the vertical support top slit,305.

FIG. 5 illustrates a first embodiment of a top wood edge form support,351, rendered from a flat formed plate, 358, of 16 gauge mild steel, andfurther comprising a top plate, 352, that is supported by the upper edgeof a joist, a nailing hole; 353, in the top plate, 352, a centraltongue, 356, two hanger side slots, 357, a left wood edge form uppersupport housing, 354, having a front face, 359, and a right wood edgeform upper support housing, 355, having a front face, 360; the frontfaces 359 and 360 are in the same plane, and together define arectangular area that is the front face of the top wood edge formsupport, 351, The central tongue, 356, may be recessed back from theplane of the front faces 359 and 360, such that the wood edge form, nowreferring to FIG. 9D, is held more closely against a verticallysupporting structure edge line, 155.

FIG. 5 further illustrates upper support structures, 307, of a firstwood edge form, 301, engaged with a left wood edge form upper supporthousing, 354, and a right wood edge form upper support housing, 355, ofa top wood edge form support, 351, of the present invention. A side viewand a top view of a wood edge form support, 351, of the presentinvention are also illustrated in FIG. 5.

FIG. 6 illustrates a second embodiment of a top wood edge form support,371, rendered from a flat formed plate, 378, of 16 gauge mild steel, andfurther comprising a top plate, 372, that is supported by the upper edgeof a joist, a nailing hole, 373, in the top plate, 372, a left wood edgeform upper support housing, 374, a right wood edge form upper supporthousing, 375, and a front face, 376. FIG. 6 further illustrates uppersupport structures, 307, of a first wood edge form, 301, engaged with aleft wood edge form upper support housing, 374, and a right wood edgeform upper support housing, 375, of a top wood edge form support, 371,of the present invention. A side view and a top view of a wood edge formsupport, 371, of the present invention are also illustrated in FIG. 6.

FIG. 6A illustrates a third embodiment of a top wood edge form support,381, identical to the top wood edge form support, 371, of FIG. 6,except, referring again to FIG. 6A, for the addition of two lower anglededge form support side plates, 382, attached by means such as welding tothe top wood edge form support, 371. The lower angled edge form supportside plates, 382, have lower front edges, 383, that are aligned with theplane of the rear inner wall, 384, of the left and right wood edge formupper support housings, 374 and 375, respectively. These lower frontedges, 383, hold wood edge forms such as the wood edge form, 301,parallel to the top wood edge form support front face, 376, whenpressure is applied to the front of the edge forms, 301, as duringconcreting.

FIG. 6B illustrates a top wood edge form support, 391, comprising thetop wood edge form support, 351, of FIG. 5, and, referring now to FIG.6A, the angled edge form support side plates, 382. Referring now to FIG.6B, the left and right wood edge form upper support housings, 354 and355 of the top wood edge form support, 391, function in an identicalway, referring now to FIG. 6A, as the left and right wood edge formupper support housings, 374 and 375, referring again to FIG. 6B, withrespect to the lower front edges, 383, of the angled edge form supportside plates, 382. The top wood edge form supports, 381 and 391, hold thewood edge form against the edge of the vertically supporting structure,155. For some low haunch applications, the top wood edge form supports351 of FIG. 5, and/or the top wood edge form supports 371 of FIG. 6, maybe substituted for the top wood edge form supports 381 and/or 391 ofFIG. 6B. This can be structurally adequate for low haunches; however, asthe haunch height increases, the weight and impact force of pouredconcrete can push the bottom of the wood edge form, 301, away from theedge of the vertically supporting structure.

FIG. 7 illustrates three embodiments of sized notch cover plates of thepresent invention, for use with the wood edge forms of FIG. 4. Referringto FIG. 7, all three notch cover plate embodiments comprise a centralwood edge form notch cover bottom tongue, 454. The wood edge form 2″notch cover plate, 451, comprises a metal edge form 2″ notch cover upperplate, 456, having a front face, 459, that is 4″ wide and 2″ high,adjoining right and left side wood edge form support structures, 460,further comprising a recessed side, 461, approximately perpendicular tothe front face, 459, and dimensioned to the width of the wood edgeforms, and a wood edge form support flange, 462, approximatelyperpendicular to the recessed side, 461, and sufficiently wide tosupport wood edge forms such as those of FIG. 4 from behind. The woodedge form 4″ notch cover plate, 452, comprises a metal edge form 4″notch cover upper plate, 457, having a front face, 459, that is 4″ wideand 4″ high, adjoining right and left side wood edge form supportstructures, 460, further comprising a recessed side, 461, approximatelyperpendicular to the front face, 459, and dimensioned to the width ofthe wood edge forms, and a wood edge form support flange, 462,approximately perpendicular to the recessed side, 461, and sufficientlywide to support wood edge forms such as those of FIG. 4 from behind. Thewood edge form 6″ notch cover plate, 453, comprises a metal edge form 6″notch cover upper plate, 458, having a front face, 459, that is 4″ wideand 6″ high, adjoining right and left side wood edge form supportstructures, 460, further comprising a recessed side, 461, approximatelyperpendicular to the front face, 459, and dimensioned to the width ofthe wood edge forms, and a wood edge form support flange, 462,approximately perpendicular to the recessed side, 461, and sufficientlywide to support wood edge forms such as those of FIG. 4 from behind. Theupper plates, 456, 457, and 458, for the illustrated embodiments, may beformed from rectangles of mild steel, 463, by bending along theillustrated dashed lines, using means such as a punch press, or a pressbrake.

The assembly of the sized notch cover plates is similar for the threeembodiments, 451, 452, and 453, illustrated in FIG. 7. Referring to thetop left exploded view, the bottom edge of the metal edge form notchcover shim, 455, is aligned with the bottom edge of the upper plate,456, and is between the upper plate, 456, and the notch cover bottomtongue, 454. The upper edge of the notch cover bottom tongue, 454, isaligned with the upper edge of the notch cover shim, 455. Both the notchcover bottom tongue, 454, and the notch cover shim, 455, are centeredwith respect to the center point of the bottom edge of the upper plate,456. The three elements can be spot welded at the center. For additionalreinforcing, the notch cover shim, 455, can also be spot welded on eachside to the upper plate, 456. All elements comprising the sized notchcover plates for the metal edge forms can be made of mild steel.Embodiments of the sized notch cover plates may have upper plates in arange of heights.

The thickness of upper plates, 456, 457, and 458, must be such as toprovide sufficient stiffness when the notch cover plates support themetal edge forms from behind against the weight and impact of pouredconcrete. The thickness and dimensions of the notch cover bottom tongue,454, must be both thick enough to securely anchor the notch coverplates, 451, 452, and 453, between the inside of the hanger body, 101,and the butt end of a joist, 130, and must be thin enough to ensure theycan be inserted even when joists, 130, are already snug against theinside of the hanger body, 101. The thickness and dimensions of thenotch cover shim, 455, must be such as to provide sufficient addedstiffness to the bottom of the upper plates, 456, 457, and 458, when thenotch cover plates, 451, 452, and 453, support metal edge forms frombehind against the weight and impact of poured concrete, and to providespace for an upper section, 172, of a wedge shim, 171, that mayoptionally be placed between the notch cover plates, 451, 452, and 453,and the butt end of a joist, 130, such that an upper section, 172, of awedge shim, 171, that may be above the top edge of the bottom tongue,454 will not engage with the back of the upper plates, 456, 457, and458, pushing the notch cover plate away from the butt end of a joist,130.

FIG. 8A illustrates an exploded view of embodiments of elements of thepresent invention comprising three adjustable and reusable joisthangers, 101, situated with respect to a dashed vertical supportstructure edge line, 155, three joists, 130, three wedge shims, 171,three metal edge form 4″ notch cover plates, 252, and a metal edge form,201.

FIG. 8B illustrates a partial assembly of the exploded elements of FIG.8A. Referring to FIG. 8B, on the left, a metal edge form 4″ notch coverplate, 252, is inserted into an adjustable and reusable joist hanger,101, and rests against the butt end of a joist, 130. In the middle, alower section, 173, of a wedge shim, 171, has been inserted between theinside of the body of an adjustable and reusable joist hanger, 101, andthe butt end of the joist, 130. As previously noted, the use of wedgeshims is optional, but may be desirable to ensure a tight fit forformwork elements.

FIG. 8C shows all three adjustable and reusable joist hanger, 101,having metal edge form 4″ notch cover plates inserted, as described withrespect to FIG. 8B.

FIG. 8D illustrates a completed assembly, comprising a metal edge form,201, supported vertically by the joists, 130, and supported against theweight and impact of the concrete by the metal edge form notch coverplates, 252, which in turn are supported by the butt ends of the joists,130. Top plywood sheathing, 161, is placed on top of the joists, 130,and the metal edge form top flanges, 209, such that the dimensioned edgeof the top plywood sheathing, 161, aligns with the front face, 202, ofthe metal edge form, 201. The joists, 130, and the top flange, 209, ofthe metal edge forms, support the top plywood sheathing, 161, againstdeflection caused by the weight and impact of poured concrete,reinforcing elements, and live loads during concreting. The height ofthe central upper notch cover, 206, and the opposite left and rightupper half notch covers, 208 and 207 respectively, as measured down fromthe adjoining top flange, 209, is such that, referring now to FIG. 3,the height of a series of upper notch cover plates, 256, 257, and 258,is in increments less than or equal, now referring again to FIG. 8D, tothe height of the central upper notch cover, 206, and the opposite leftand right upper half notch covers, 208 and 207 respectively. Therefore,whatever the height of the notch gap, measured with respect to the loweredge of the notch covers or notch half covers, 206, 207 and 208, and theupper surface of the top lip, 102, of the adjustable joist hanger, 101,that is covered by a sized notch cover plate, such as the 4″ notch coverplate 252, one embodiment of a sized notch cover plate will be availablethat will fully cover the notch gap, but will not be as high as thedistance from the metal edge form top flange, 209, and the upper surfaceof the top lip, 102.

The FIG. 9 series, illustrating deployment of embodiments of wood edgeforms of the present invention, is similar to the FIG. 8 series,illustrating deployment of embodiments of metal edge forms of thepresent invention. FIG. 9A illustrates a partial assembly and a partialexploded view of embodiments of elements of the present inventioncomprising adjustable and reusable joist hangers, 101, positioned withrespect to a vertical support structure edge line, 155, joists, 130, afirst wood edge form, 301, a second wood edge form, 302, a third woodedge form, 303, a top wood edge form support, 351, top wood edge formsupports, 371, wood edge form 2″ notch cover plates, 451, a wood edgeform 4″ notch cover plate, 452, a middle notch cover rectangle, 481, amiddle notch cover rectangle bent, 482, and a middle notch coverrectangle with tongue, 483, further comprising a tongue, 485.

FIG. 9B illustrates the assembled elements of FIG. 9A, furthercomprising top plywood sheathing, 161, but without the use, referringnow to FIG. 9A, of the middle notch cover rectangle, 481, or the middlenotch cover rectangle with tongue, 483. Referring now to FIG. 9B, thedeployment of the wood edge form 4″ notch cover plate, 452, illustratesthat in combination with the top wood edge form support, 371, the spacebetween wood edge forms, 301 and 303, adjacent to the left adjustableand reusable joist hanger, 101, is completely covered. The height of thetop wood edge form supports, 351 and 371, is such that, referring now toFIG. 7, the height of a series of upper notch cover plates, 456, 457,and 458, is in increments less than or equal, now referring again toFIG. 9B, to the height of the top wood edge form supports, 351 and 371.Therefore, whatever the height of the notch gap, measured with respectto the lower edge of the top wood edge form supports, 351 and 371, andthe upper surface of the top lip, 102, of the adjustable joist hanger,101, that is covered by a sized notch cover plate, such as the 4″ notchcover plate 452, one embodiment of a sized notch cover plate will beavailable that will fully cover the notch gap, but will not be as highas the distance from the lower surfaces of the top plates, 352 of FIG.5, and 372 of FIG. 6, now referring to FIG. 9B, of the top wood edgeform supports, 351 and 371, and the upper surface of the top lip, 102.

Continuing to refer to FIG. 9B, the center adjustable and reusable joisthanger, 101, illustrates the deployment of a top wood edge form support,371, and a wood edge 2″ notch cover plate, 451. While these two elementsprovide top and bottom support for the wood edge forms, 301 and 303, andhold the bottom of the edge forms tight against the vertical supportstructure edge line, 155, there is a gap between the top wood edge formsupport, 371, and the wood edge 2″ notch cover plate, 451. This gap canbe covered with duct tape in some cases. Alternatively, as illustratedin FIG. 9C, this gap can be covered with a middle notch cover rectangle,482, placed at the bottom between the wood edge 2″ notch cover plate,451, and the butt end of the joist, and bent at the top of the joist.Referring now to FIG. 9B, the right adjustable and reusable joisthanger, 101, illustrates the deployment of a top wood edge form support,351, and a wood edge 2″ notch cover plate, 451. While these two elementsprovide top and bottom support for the wood edge forms, 301 and 303, andhold the bottom of the edge forms tight against the vertical supportstructure edge line, 155, there is a gap between the top wood edge formsupport, 351, and the wood edge 2″ notch cover plate, 451. In addition,referring now to FIG. 5, the hanger side slots, 357, must be covered,referring now to FIG. 9B, to close up the formwork structure. These gapsand openings can be covered with duct tape in some cases. Alternatively,referring now to FIG. 9C, these gaps and openings can be covered with amiddle notch cover rectangle, 482, placed at the bottom between the woodedge 2″ notch cover plate, 451, and the butt end of the joist, and bentat the top of the joist, covering the central area, of the top wood edgeform support, 351.

FIG. 9D illustrates the use of a top wood edge form support, 351, wherea low haunch is required. The central tongue, 356, of the top wood edgeform support, 351, is partially inserted between the adjustable andreusable hanger, 101, and the butt edge of the joist. The top wood edgeform support, 351, can be used for haunches such that the centraltongue, 356 is fully inserted. The openings left by the hanger sideslots, 357, can be covered by duct tape, or by the use of a middle notchcover rectangle with tongue, 483, also illustrated as bent, 484,comprising a lower tongue section, 485, that is inserted at the bottombetween the body of the adjustable and reusable joist hanger, 101, andthe central tongue, 356, of the top wood edge form support, 351, andthat is bent at the top of the joist. The middle notch cover rectanglewith tongue, 483, may also be used with the top wood edge form support,371, of FIG. 6, with higher haunches, and also, referring now to FIG.6B, with the top wood edge form supports having angled edge form supportside plates, 381 and 391.

FIG. 10 illustrates an embodiment of an element of the presentinvention, comprising a wedge shim 171, having a series of horizontalslits, 174, symmetrically on each side of the central vertical axis ofthe wedge shim, 171. The depth of these horizontal slits, 174, can bedimensioned with respect to wedge shim slit depth alignment lines, 175,such that the depth of the horizontal slits, 174, decreases as the widthof the wedge shim decreases, and the depth of the horizontal slits, 174,increases as the width of the wedge shim increases. These shims can beused to advantage with respect to embodiments of other elements of thepresent invention, because a top section of the wedge shim can be brokenoff by pulling the top portion of the wedge shim to either side.Standard shims can typically be broken off by pulling forward, butcannot be broken off by pulling to either side. Referring now to FIG. 3,the advantage of limiting the height of an upper section, 172, of awedge shim, 171, is that a short upper section, 172, will not tend topush notch cover plates away from the butt ends of joists, while alonger upper section, 172, may do so.

Referring to FIG. 1, while this specification has focused on embodimentsof the present invention deployed with adjustable and reusable joisthangers, 101, having a top lip structure, 102, that is wider than thejoist, 130, it should be understood that alternative embodiments of thepresent invention may be deployed with other means for suspendingjoists, and variants of embodiments of the present invention maycomprise notch widths sized to the width of joists, or other supportingmembers, rather than to the width of the top lip structure, 102, of theembodiment of the adjustable and reusable joist hanger, 101.

It will be understood that embodiments of joist hangers of the presentinvention may be adjustable. It will be further understood that whilethis specification has focused on embodiments of the present inventionrendered with respect to vertical edge gaps, alternative embodiments ofthe present invention may be employed when edge gaps are set at an angleto the vertical plane. It will be further understood that embodiments ofthe wood edge forms may have curved surfaces.

The modular edge form system of the present invention offers theseadvantages with respect to the prior art:

-   -   It is suitable for use with adjustable and reusable hangers        suspended on a top surface of a vertical support structure.    -   It provides means for closing the edge gap for a range of haunch        heights from zero to eight inches, or more.    -   It provides deflection support for the edges of top sheathing.    -   It provides means for bracing an edge form against a vertical        support structure to prevent or minimize leaking of concrete.    -   It provides means for forming suspended concrete slabs with        curved perimeters.    -   It comprises cooperative modular elements that can be combined        in one or multiple way(s), as needed for a particular        application.    -   It is design for structural integration with other modular        systems for forming suspended slabs.    -   It can be practiced with minimal or no use of nails and/or        screws, resulting in faster and easier assembly and tear down,        and no rusted nails remaining on the site for years.

1. A modular edge form system for cast in place suspended concreteslabs, comprising: a. metal edge forms, having a front face, a topflange which depends on a joist, one or more notches and/or side halfnotches sized to the outer width of a joist hanger, one or more uppernotch covers and/or half notch covers, and one or more bottomreinforcing flange sections between the notches, and b. a series ofsized notch cover plates having faces wider than the metal edge formnotches and/or adjoining half-notches, and having a range of heightssuch that the height increments are equal to or less than the height ofthe said upper notch covers and/or half notch covers of the said metaledge forms, and having tongues that are inserted between the butt end ofa joist and the inner central wall of a joist hanger depending on avertically supporting structure, such that the sized notch cover plateshold the said metal edge forms against the edge of the said verticallysupporting structure, and c. top sheathing placed on top of the joistsand on the metal edge form top flanges, and dimensioned such that theedge of the sheathing aligns with the front face of the metal edgeforms.
 2. The modular edge form system of claim 1 further comprisingfront faces of the said metal edge form that are vertical.
 3. Themodular edge form system of claim 1 further comprising bottomreinforcing flanges of the said metal edge form that further comprise areinforcing fold.
 4. The modular edge form system of claim 1 furthercomprising a nailing hole in the said metal edge form top flange.
 5. Themodular edge form system of claim 1 further comprising a said joisthanger that is adjustable.
 6. The modular edge form system of claim 1further comprising a wedge shim having a series of horizontal slitssymmetrically on each side of a central vertical axis, the depth ofthese horizontal slits being dimensioned with respect to the varyingthickness of the wedge.
 7. A modular edge form system for cast in placesuspended concrete slabs, comprising: a. wood edge forms, comprising afront face and upper support structures on each side, and b. top woodedge form support structures, comprising a front face, and furthercomprising wood edge form upper support housings on each side whichengage with and support the wood edge form upper support structures, andfurther comprising a top plate which depends on a joist, and c. thejoist depending on a joist hanger, the said joist hanger in turndepending on a vertically supporting structure, and d. top sheathingplaced on top of the joists and on the wood edge forms, and dimensionedsuch that the edge of the sheathing aligns with the front face of thewood edge forms.
 8. The modular edge form system of claim 7, furthercomprising one or a series of sized notch cover plates, the said notchcover plates further comprising a central lower tongue, and furthercomprising faces that are sized to the outer width of the said joisthangers, recessed outer flanges sized to hold the said wood edge formsagainst the edge of the said vertically supporting structure, and, for aseries of the said sized notch cover plates, front face heightincrements that are less than the height of the front face of the saidtop wood edge form support structures.
 9. The modular edge form systemof claim 7, further comprising a said top wood edge form support topplate having a nailing hole.
 10. The modular edge form system of claim7, further comprising a said top wood edge form support top plate havinga recessed front face central tongue sized to be inserted within a saidjoist hanger, and further comprising, between the said central tongueand the said upper support housing front faces, gaps sized to the widthof the outer sides of the said joist hanger.
 11. The modular edge formsystem of claim 7, further comprising a said top wood edge form supporttop plate having a continuous rectangular front face comprising the saidupper support housings.
 12. The modular edge form system of claim 7,further comprising a said top wood edge form support having lower angledsupport side plates perpendicular to edge of the vertical supportstructure, and having lower front edges that are aligned with the planeof a rear inner wall of the said upper support housings.
 13. The modularedge form system of claim 7 further comprising front faces of the saidwood edge form that are vertical.
 14. The modular edge form system ofclaim 7 further comprising a said joist hanger that is adjustable. 15.The modular edge form system of claim 7 further comprising a wedge shimhaving a series of horizontal slits symmetrically on each side of acentral vertical axis, the depth of these horizontal slits beingdimensioned with respect to the varying thickness of the wedge.
 16. Themodular edge form system of claim 7 further comprising a bendable middlenotch cover rectangle, having a lower tongue section.